But like a lot of Americans, she's not looking to that number as a signal to retire.

Her predecessors, Walter Sickles and Earl Lennard, were both 62 when they announced their retirements. Elia, who turned 65 in November, is still going strong.

"I have no plans to retire," she said last week, following a School Board workshop session in which one member referred to her with an expletive while walking out the door.

"I would urge you to look at my schedule and my calendar. I am at work at 6 or 6:30 every morning and out until 7 at night. Nobody believes I have lost any energy and I have a passion to support the students in this county."

Twice she noted that "60 is the new 30."

Unlike many large school districts, Hillsborough has a history of longevity in its leadership. The superintendent's position is a prime example.

Elia signed her contract in 2005. Since then, Pasco County has had two superintendents. Pinellas County has had four.

Hillsborough also has a tradition of hiring top administrators from within the ranks, making it likely Elia's replacement, when that time comes, will be a district employee. Anticipating a wave of retirements, the district last year adopted an administrative reorganization with three phases.

Jeffrey Eakins, the former head of federal programs, was named assistant superintendent for performance management and community support in March, then deputy superintendent in July. He is 48. Cathy Valdes was promoted in January from chief facilities officer to deputy superintendent. She is 63.

Elia, who earns more than $270,000 a year in a three-year contract, would not talk about any plan of succession for her.

"Whenever that happens, it will be a board decision," she said. "I really have no idea how they will proceed."

A district employee since 1986, Elia was at the vanguard of the magnet school movement, with more than 30 programs opening before and after she became superintendent. She cemented her national profile in 2009, when the Bill and Melinda Gates Foundation awarded Hillsborough a $100 million grant to revamp its teacher evaluation and mentoring system.

But School Board support, once nearly unanimous, wavered in late 2012 when it was revealed that a special needs child had died 10 months earlier after a ride on a school bus. That news followed scandals in the Armwood High School football program and in an urban teaching program that struggled to provide the scholarships it promised.

It took Elia nearly a year to secure approval for a security plan for elementary schools, and even then the board approved only the first of four phases.

Despite these rough patches, none of the board members questioned cited age as an issue.

"I'm not even going to comment on that, because I will be a 65-year-old woman," said April Griffin, the board member who had muttered the expletive about Elia on Tuesday.

But member Stacy White, while agreeing age shouldn't matter, said length of tenure might.

"Nine years is a long time, even for Hillsborough," he said. "I think a decade at that pace would be taxing on anyone. At some point you might just think it's time to pass the baton."

As for what comes next, White acknowledged that Hillsborough enjoys a degree of stability and continuity by hiring from within. He said he believes the board should do a national search when it next looks for a superintendent.

He also said he is impressed by Eakins, and thinks it is equally important to groom people for leadership. "I learned a long time ago in the private sector that a good manager should always look to have someone to replace them," he said.

Member Cindy Stuart, while noting it would be hard to find anyone who can keep up with Elia, agreed that the board should look ahead.

"No matter what MaryEllen Elia says, or what a good job she is doing, strategically, the board has to talk about it," she said. "We do not want it to be an emergency. We have seen what other districts go through. We have not had this conversation."